1. Field of the Invention
The present invention relates to RF signals, and more particularly to an inexpensive method of measuring the frequency of Continuous Wave and Wide Pulse RF signals in real-time or near real-time.
2. Description of Related Art
Radar and electronic counter measure (ECM) systems commonly employ continuous wave (CW) or wide pulse (pulses with widths &gt;5 microsec) RF signals. The frequency of such an RF signal emitted by these systems is an important characteristic that must be accurately measured to assess a system's performance.
The conventional method for measuring RF frequency is to use expensive equipment such as electronic counters, spectrum analyzers, synchronous detectors and digital frequency discriminators. Microwave counters EIP 1230A and 1231A manufactured by EIP Microwave, Inc. and the Hewlett Packard electronic counter HP 5361B are examples of instruments currently in use to measure RF frequencies. These instruments, however, are expensive, bulky and require specialized hardware. They also do not provide the required frequency measurement accuracy for state-of-the-art radar and ECM systems. The accuracy required for these systems is often &lt;100 hertz for signals with frequencies of up to 40 gigahertz.